What does a field duplicate indicate?

What does a field duplicate indicate?

• A. It indicates instrument precision under field conditions.
• B. It indicates sampling precision and field heterogeneity when collected identically.
• C. It indicates method calibration drift.
• D. It indicates sample preservation quality.

Answer: (B)

Field duplicates show how much variability is introduced during sample collection and the natural differences in the field at the sampling site. They’re taken identically from the same location to isolate variability from the sampling process and environmental heterogeneity, not from lab analysis. If the two samples yield similar results, the sampling is precise and the site is fairly homogeneous for that analyte. Large differences indicate sampling imprecision or true heterogeneity in the field. This concept is distinct from instrument calibration drift, which concerns changes in measurement accuracy over time, and from sample preservation quality, which relates to how well samples are kept after collection.

Field duplicates show how much variability is introduced during sample collection and the natural differences in the field at the sampling site. They’re taken identically from the same location to isolate variability from the sampling process and environmental heterogeneity, not from lab analysis. If the two samples yield similar results, the sampling is precise and the site is fairly homogeneous for that analyte. Large differences indicate sampling imprecision or true heterogeneity in the field. This concept is distinct from instrument calibration drift, which concerns changes in measurement accuracy over time, and from sample preservation quality, which relates to how well samples are kept after collection.